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/*
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 * Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos
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 * All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
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package java.time.chrono;

import static java.time.temporal.ChronoUnit.SECONDS;

import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInput;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.Serializable;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.temporal.ChronoField;
import java.time.temporal.ChronoUnit;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalField;
import java.time.temporal.TemporalUnit;
import java.time.zone.ZoneOffsetTransition;
import java.time.zone.ZoneRules;
import java.util.List;
import java.util.Objects;

/**
 * A date-time with a time-zone in the calendar neutral API.
 * <p>
 * {@code ZoneChronoDateTime} is an immutable representation of a date-time with a time-zone.
 * This class stores all date and time fields, to a precision of nanoseconds,
 * as well as a time-zone and zone offset.
 * <p>
 * The purpose of storing the time-zone is to distinguish the ambiguous case where
 * the local time-line overlaps, typically as a result of the end of daylight time.
 * Information about the local-time can be obtained using methods on the time-zone.
 *
 * @param <D> the concrete type for the date of this date-time
 * @implSpec This class is immutable and thread-safe.
 * @serial Document the delegation of this class in the serialized-form specification.
 * @since 1.8
 */
final class ChronoZonedDateTimeImpl<D extends ChronoLocalDate>
    implements ChronoZonedDateTime<D>, Serializable {

  /**
   * Serialization version.
   */
  private static final long serialVersionUID = -5261813987200935591L;

  /**
   * The local date-time.
   */
  private final transient ChronoLocalDateTimeImpl<D> dateTime;
  /**
   * The zone offset.
   */
  private final transient ZoneOffset offset;
  /**
   * The zone ID.
   */
  private final transient ZoneId zone;

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance from a local date-time using the preferred offset if possible.
   *
   * @param localDateTime the local date-time, not null
   * @param zone the zone identifier, not null
   * @param preferredOffset the zone offset, null if no preference
   * @return the zoned date-time, not null
   */
  static <R extends ChronoLocalDate> ChronoZonedDateTime<R> ofBest(
      ChronoLocalDateTimeImpl<R> localDateTime, ZoneId zone, ZoneOffset preferredOffset) {
    Objects.requireNonNull(localDateTime, "localDateTime");
    Objects.requireNonNull(zone, "zone");
    if (zone instanceof ZoneOffset) {
      return new ChronoZonedDateTimeImpl<>(localDateTime, (ZoneOffset) zone, zone);
    }
    ZoneRules rules = zone.getRules();
    LocalDateTime isoLDT = LocalDateTime.from(localDateTime);
    List<ZoneOffset> validOffsets = rules.getValidOffsets(isoLDT);
    ZoneOffset offset;
    if (validOffsets.size() == 1) {
      offset = validOffsets.get(0);
    } else if (validOffsets.size() == 0) {
      ZoneOffsetTransition trans = rules.getTransition(isoLDT);
      localDateTime = localDateTime.plusSeconds(trans.getDuration().getSeconds());
      offset = trans.getOffsetAfter();
    } else {
      if (preferredOffset != null && validOffsets.contains(preferredOffset)) {
        offset = preferredOffset;
      } else {
        offset = validOffsets.get(0);
      }
    }
    Objects.requireNonNull(offset, "offset");  // protect against bad ZoneRules
    return new ChronoZonedDateTimeImpl<>(localDateTime, offset, zone);
  }

  /**
   * Obtains an instance from an instant using the specified time-zone.
   *
   * @param chrono the chronology, not null
   * @param instant the instant, not null
   * @param zone the zone identifier, not null
   * @return the zoned date-time, not null
   */
  static ChronoZonedDateTimeImpl<?> ofInstant(Chronology chrono, Instant instant, ZoneId zone) {
    ZoneRules rules = zone.getRules();
    ZoneOffset offset = rules.getOffset(instant);
    Objects.requireNonNull(offset, "offset");  // protect against bad ZoneRules
    LocalDateTime ldt = LocalDateTime
        .ofEpochSecond(instant.getEpochSecond(), instant.getNano(), offset);
    ChronoLocalDateTimeImpl<?> cldt = (ChronoLocalDateTimeImpl<?>) chrono.localDateTime(ldt);
    return new ChronoZonedDateTimeImpl<>(cldt, offset, zone);
  }

  /**
   * Obtains an instance from an {@code Instant}.
   *
   * @param instant the instant to create the date-time from, not null
   * @param zone the time-zone to use, validated not null
   * @return the zoned date-time, validated not null
   */
  @SuppressWarnings("unchecked")
  private ChronoZonedDateTimeImpl<D> create(Instant instant, ZoneId zone) {
    return (ChronoZonedDateTimeImpl<D>) ofInstant(getChronology(), instant, zone);
  }

  /**
   * Casts the {@code Temporal} to {@code ChronoZonedDateTimeImpl} ensuring it bas the specified
   * chronology.
   *
   * @param chrono the chronology to check for, not null
   * @param temporal a date-time to cast, not null
   * @return the date-time checked and cast to {@code ChronoZonedDateTimeImpl}, not null
   * @throws ClassCastException if the date-time cannot be cast to ChronoZonedDateTimeImpl or the
   * chronology is not equal this Chronology
   */
  static <R extends ChronoLocalDate> ChronoZonedDateTimeImpl<R> ensureValid(Chronology chrono,
      Temporal temporal) {
    @SuppressWarnings("unchecked")
    ChronoZonedDateTimeImpl<R> other = (ChronoZonedDateTimeImpl<R>) temporal;
    if (chrono.equals(other.getChronology()) == false) {
      throw new ClassCastException("Chronology mismatch, required: " + chrono.getId()
          + ", actual: " + other.getChronology().getId());
    }
    return other;
  }

  //-----------------------------------------------------------------------

  /**
   * Constructor.
   *
   * @param dateTime the date-time, not null
   * @param offset the zone offset, not null
   * @param zone the zone ID, not null
   */
  private ChronoZonedDateTimeImpl(ChronoLocalDateTimeImpl<D> dateTime, ZoneOffset offset,
      ZoneId zone) {
    this.dateTime = Objects.requireNonNull(dateTime, "dateTime");
    this.offset = Objects.requireNonNull(offset, "offset");
    this.zone = Objects.requireNonNull(zone, "zone");
  }

  //-----------------------------------------------------------------------
  @Override
  public ZoneOffset getOffset() {
    return offset;
  }

  @Override
  public ChronoZonedDateTime<D> withEarlierOffsetAtOverlap() {
    ZoneOffsetTransition trans = getZone().getRules().getTransition(LocalDateTime.from(this));
    if (trans != null && trans.isOverlap()) {
      ZoneOffset earlierOffset = trans.getOffsetBefore();
      if (earlierOffset.equals(offset) == false) {
        return new ChronoZonedDateTimeImpl<>(dateTime, earlierOffset, zone);
      }
    }
    return this;
  }

  @Override
  public ChronoZonedDateTime<D> withLaterOffsetAtOverlap() {
    ZoneOffsetTransition trans = getZone().getRules().getTransition(LocalDateTime.from(this));
    if (trans != null) {
      ZoneOffset offset = trans.getOffsetAfter();
      if (offset.equals(getOffset()) == false) {
        return new ChronoZonedDateTimeImpl<>(dateTime, offset, zone);
      }
    }
    return this;
  }

  //-----------------------------------------------------------------------
  @Override
  public ChronoLocalDateTime<D> toLocalDateTime() {
    return dateTime;
  }

  @Override
  public ZoneId getZone() {
    return zone;
  }

  @Override
  public ChronoZonedDateTime<D> withZoneSameLocal(ZoneId zone) {
    return ofBest(dateTime, zone, offset);
  }

  @Override
  public ChronoZonedDateTime<D> withZoneSameInstant(ZoneId zone) {
    Objects.requireNonNull(zone, "zone");
    return this.zone.equals(zone) ? this : create(dateTime.toInstant(offset), zone);
  }

  //-----------------------------------------------------------------------
  @Override
  public boolean isSupported(TemporalField field) {
    return field instanceof ChronoField || (field != null && field.isSupportedBy(this));
  }

  //-----------------------------------------------------------------------
  @Override
  public ChronoZonedDateTime<D> with(TemporalField field, long newValue) {
    if (field instanceof ChronoField) {
      ChronoField f = (ChronoField) field;
      switch (f) {
        case INSTANT_SECONDS:
          return plus(newValue - toEpochSecond(), SECONDS);
        case OFFSET_SECONDS: {
          ZoneOffset offset = ZoneOffset.ofTotalSeconds(f.checkValidIntValue(newValue));
          return create(dateTime.toInstant(offset), zone);
        }
      }
      return ofBest(dateTime.with(field, newValue), zone, offset);
    }
    return ChronoZonedDateTimeImpl.ensureValid(getChronology(), field.adjustInto(this, newValue));
  }

  //-----------------------------------------------------------------------
  @Override
  public ChronoZonedDateTime<D> plus(long amountToAdd, TemporalUnit unit) {
    if (unit instanceof ChronoUnit) {
      return with(dateTime.plus(amountToAdd, unit));
    }
    return ChronoZonedDateTimeImpl.ensureValid(getChronology(),
        unit.addTo(this, amountToAdd));   /// TODO: Generics replacement Risk!
  }

  //-----------------------------------------------------------------------
  @Override
  public long until(Temporal endExclusive, TemporalUnit unit) {
    Objects.requireNonNull(endExclusive, "endExclusive");
    @SuppressWarnings("unchecked")
    ChronoZonedDateTime<D> end = (ChronoZonedDateTime<D>) getChronology()
        .zonedDateTime(endExclusive);
    if (unit instanceof ChronoUnit) {
      end = end.withZoneSameInstant(offset);
      return dateTime.until(end.toLocalDateTime(), unit);
    }
    Objects.requireNonNull(unit, "unit");
    return unit.between(this, end);
  }

  //-----------------------------------------------------------------------

  /**
   * Writes the ChronoZonedDateTime using a
   * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
   *
   * @return the instance of {@code Ser}, not null
   * @serialData <pre>
   *  out.writeByte(3);                  // identifies a ChronoZonedDateTime
   *  out.writeObject(toLocalDateTime());
   *  out.writeObject(getOffset());
   *  out.writeObject(getZone());
   * </pre>
   */
  private Object writeReplace() {
    return new Ser(Ser.CHRONO_ZONE_DATE_TIME_TYPE, this);
  }

  /**
   * Defend against malicious streams.
   *
   * @param s the stream to read
   * @throws InvalidObjectException always
   */
  private void readObject(ObjectInputStream s) throws InvalidObjectException {
    throw new InvalidObjectException("Deserialization via serialization delegate");
  }

  void writeExternal(ObjectOutput out) throws IOException {
    out.writeObject(dateTime);
    out.writeObject(offset);
    out.writeObject(zone);
  }

  static ChronoZonedDateTime<?> readExternal(ObjectInput in)
      throws IOException, ClassNotFoundException {
    ChronoLocalDateTime<?> dateTime = (ChronoLocalDateTime<?>) in.readObject();
    ZoneOffset offset = (ZoneOffset) in.readObject();
    ZoneId zone = (ZoneId) in.readObject();
    return dateTime.atZone(offset).withZoneSameLocal(zone);
    // TODO: ZDT uses ofLenient()
  }

  //-------------------------------------------------------------------------
  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj instanceof ChronoZonedDateTime) {
      return compareTo((ChronoZonedDateTime<?>) obj) == 0;
    }
    return false;
  }

  @Override
  public int hashCode() {
    return toLocalDateTime().hashCode() ^ getOffset().hashCode() ^ Integer
        .rotateLeft(getZone().hashCode(), 3);
  }

  @Override
  public String toString() {
    String str = toLocalDateTime().toString() + getOffset().toString();
    if (getOffset() != getZone()) {
      str += '[' + getZone().toString() + ']';
    }
    return str;
  }


}
